This significance has increased dramatically with the rise of mobile internet browsing. Today, 64% of smartphone users expect a page to load in less than four seconds.
Because of this growing expectation of fast page loading, Google has recognized its importance in providing a satisfying user experience.
This has prompted them to use mobile page load speed as a ranking factor within their search algorithm. And with Google rolling out mobile-first indexing last year, put simply, your website will suffer in SEO if your core pages load slowly.